This invention pertains to volutes and scrolls, and the like, such as are incorporated in fluid-working devices, namely turbines, centrifugal pumps, and compressors. Exemplary thereof are those shown in U.S. Pat. No. 4,181,466, issued on Jan. 1st, 1980, to Bruce R. Owen for a Centrifugal Compressor and Cover; U.S. Pat. No. 4,743,161, granted on May 10th, 1988, for Compressors, to Frank B. Fisher, et al; and U.S. Pat. No. 2,925,952, for a Radial-Flow Compressor, issued on Feb. 23rd, 1960, to Alexander Garve. The scrolls depicted in the aforesaid patents are of the overhung type, which are advantageous when compared to the more conventional, symmetrical volute or scroll. However, in that the overhung scroll is so difficult to cast, it is not commonly used in commercial centrifugal pumps. In addition, the overhung scroll has only a limited access to the inner, scroll passage for the purposes of cleaning and polishing. The prior art scrolls, further, offer no facility for selectively modifying the scroll throat area. What has been sought in this art, then, is an improved scroll geometry which will facilitate (a) casting, (b) cleaning and polishing of the inner scroll passage, (c) means for modifying the scroll throat area, and (d) with removal of the front cover, gives access to the impeller for cleaning and/or removal of debris from the inlet and the impeller periphery.